Free Flight
Earl Stahl PT-19 in work
Free Flight, the main subject of my collection of web pages. More than it's simple sounding name implies, we don't merely wind up rubber powered planes or start the engine of hefty glow powered contraptions and give them a chuck. Yes they fly without benefit or hinderance of physical control inputs, but if the modeler has done their job correctly the model will fly in a predictable fashion and for a predetermined amount of time.
A brand new plane begins with a careful unpowered glide over something that is as close to a section of tall grass as we can find. If that looks promising the plane may get a few more test glides. Assuming this phase goes well we power the plane for a very short period of time, as this may change things completely. If that goes well then it gets more power and we watch the pattern that the plane flies in. If the model were to fly in a perfectly straight line then we would be walking quite some distance to pick up our better models. We would rather it circle around near us, because getting to see it fly by is what puts a smile on our faces. Some modelers force their models to fly in either right hand or left hand circles, some think high wing planes should circle left while low wingers should circle right. Others just let the plane decide and go with it. It is quite possible to have a model that flies in ever increasing left circles, go straight for a bit and then glide to the right.
When I started I flew my planes outdoors because, well, I lived in a house. I was in the habit of taking my kids for walks to parks or schools and wanted something to do while they played. I could have flown my first couple of attempts in a port-a-potty without hitting the walls. But once I discovered some of the planes in the "sport" catagory listed below things changed. Before too long it took careful counting of the number of turns in the rubber motor to make sure my plane would not venture beyond the school yard.
Modelers who are into outdoor flying (Old Timers, Nostalgia, and larger rubber powered planes) look for a boost from mother nature in the form of a thermal. A thermal is a rising bubble of air which can either add a minute or two to your flight or steal even a heavy plane forever (we call those "trash haulers"). To combat the loss of a prized plane, outdoor modelers adapt one of a variety of dethermalizers, or DTs. These clever devices can be mechanical timers or a piece of fiber "fuse" held in a rubber tube. When the fuse burns short enough it burns through a rubber band which then releases the same way the mechanical type does. What it releases can also change from model to model. One of the more common kind pops the horizontal stabilizer up at 45 degrees. Others pop up the wing and still others pop the entire wing loose from the airplane (held captive by a piece of light line and a snap swivel). Avaition is through for the moment. Though perhaps not as fast as a filing cabinet or shotgunned duck, the plane descends rapidly and directly downward.
Indoor models are a different bag entirely. Flying inside eliminates thermals which helps to level the playing field in a competition. Lack of wind allows planes to be built very lightly. Planes found indoors vary from lightly built scale planes (such as peanuts) to penny planes (named for the weight of a penny, 3.2 grams) or EZ-Bs which make a penny plane look like a Kenworth. Some of these planes have broken the one hour barrier for a single flight. The owner counts the revolutions of the slow moving propeller. People walk slow, whisper and fret that someone might open a door or turn on the ventilation system.
The various types of Free Flight models are: